Bruce Willis makes his getaway, by skateboard and buck naked, when he’s caught in bed with a young client in an early moment in “Once Upon a Time in Venice.”

Which is pretty much all you need to know about this action/comedy. Well, that and it’s not about Venice, Italy, but Venice Beach, where filmmakers can attract a long line of solid B-listers to pop into their movie, if only for a name-for-the-credits for the foreign markets.

So David Arquette swoops through a shot, whooping about “getting the Band back together,” and Kal Penn can play his first and last Indian-American convenience store owner.

And Bruce? At 62, he’s still fit enough to not make you strain your eyes to ensure that yes, that’s a stunt double streaking through downtown Venice, in the dark and in the buff, crawling out of windows, etc. That sprint through a crowded bar, still starkers? Yeah, that’s Bruce, only in the trailers he’s wearing gym shorts. So some digital stripping or alternative take business is going on somewhere.

Willis plays Steve, elder statesman of Venice, the only private eye in the town, given to hectoring lectures of the 10 year-old sk8Rboyz about “weed, hookers and blow.”

Then he and the film’s narrator, his “partner” (Thomas Middleditch of “Silicon Valley,” a poor man’s Simon Helberg) land a case. They’re to catch whoever is spraying obscene graffiti on an apartment building owned by “Lou the Jew” (Adam Goldberg, of course).

Then there’s the favor, retrieving a lowrider ’60s Chevy Impala for the pizza guy (Adrian Martinez). That runs Steve afoul of Spyder, the drug dealer (Jason Momoa). And Spyder is the guy who ends up with Steve’s “Parson” Jack Russell terrier, beloved by his niece (Emily Robinson) and sister (Famke Janssen), who are going through a rough time now. Steve is damned sure going to get that dog back.

“Venice” is the sort of random, rambling thriller where everybody the private eye meets — from drug dealer to real estate hustler, loan shark to surf shop pal (John Goodman) going through a divorce, says, “Tell you what I’m gonna do,” followed by “do this for me” or “get that for me” and “I’ll help you out.”

The messy tangle of the plot, which involves Steve-Bruce getting knocked out, more than once, does little more than throw a whole lot of potentially silly stuff against the screen — some of it landing laughs.

Willis naked on a skateboard, Momoa’s chill but grudge-toting drug dealer, Middleditch’s efforts to tail a subject into her sex addict’s anonymous meeting and “fit it,” and oh one of other epic moment — Willis, in a dress, wig and makeup, chased by a cohort of Venice’s transvestite hookers — those are kind of funny.

Given a bigger budget, this could have gotten the script doctoring it needed to pack in more laughs. I counted maybe five. And they’d have had the money to use “The First Time Ever I Saw Your Face” as a gag, or “real” surf music by Dick Dale, or “real” Beach Boys tunes — instead of the nakedly obvious rip-offs of these tunes tucked into the score.

The 50ish Cullen Brothers produced the Willis/Kevin Smith debacle “Cop Out,” so it’s not like they’re novices. This is as good as they’re going to get.

And Willis? He’s a young 62, but this is kind of where his career has gone — tepid, limited-release action comedies without the hot property script, the big paycheck or budget to quite come off.

MPAA Rating: unrated, with violence, nudity, profanity

Cast: Bruce Willis, John Goodman, Jason Mamoa, Famke Janssen, Thomas Middleditch, Adam Goldberg, Wood Harris

Credits:Written and directed by Marc and Robb Cullen . A Voltage release.

Running time: 1:34